[Ips-dsgr] SWS Daily Report - 25 May 21 issued 2330 UT on 25 May 2021
Regional Warning Centre
rwc at ips.gov.au
Wed May 26 09:30:07 EST 2021
SUBJ: SWS DAILY SOLAR AND GEOPHYSICAL REPORT
ISSUED AT 2330UT/25 MAY 2021 BY Space Weather Services
FROM THE AUSTRALIAN SPACE FORECAST CENTRE
SUMMARY FOR 25 MAY AND FORECAST FOR 26 MAY - 28 MAY
STATUS INDICATORS SOL:GREEN MAG:** RED ** ION: ** YELLOW **
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1A. SOLAR SUMMARY
Activity 25 May: Very low
Flares: none.
Observed 10.7 cm flux/Equivalent Sunspot Number for 25 May: 84/26
1B. SOLAR FORECAST
26 May 27 May 28 May
Activity Low Low Low
Fadeouts None expected None expected None expected
10.7cm/SSN 82/23 82/23 78/17
COMMENT: Solar activity was very low on UT day 25 May with a
series of B-class flares from active regions AR 2824 (Cai-Beta)
and AR 2826 (Bxo-Beta). The only other active region on the visible
disk is AR 2825 in the North East quadrant. There was a CME in
the Lasco and Stereo-A images on 24 May at 17 UT but it appears
to be from the far side of the Sun and further analysis is required.
Another CME was just starting to appear in Stereo-A on 25 May
at 20 UT towards the West and further analysis will be done as
more data becomes available. There were no other CMEs in the
coronagraph images. Solar activity is expected to be low with
a small chance of M-class flares for the next three
UT days 26-28 May. On the UT day 25 May, the solar wind speed
was between 305 km/s and 330 km/s. The IMF (Bt) peaked at 4 nT
and the north-south IMF component (Bz) range was +2/-4 nT. The
solar wind speed is expected to be elevated to strongly enhanced
levels on UT days 26-28 May when the 22-23 May CMEs arrive at
Earth. ACE EPAM data indicates an energetic ion enhancement event
beginning 24/1545UT, which can be a precursor to increased geomagnetic
activity over next 24-36 hours.
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2A. MAGNETIC SUMMARY
Geomagnetic field for Australian Region 25 May: Quiet
Estimated Indices 25 May : A K
Australian Region 0 00000101
Cocos Island 1 10000101
Darwin 1 00100101
Townsville 1 11100101
Learmonth 1 00-10101
Alice Springs 0 00000001
Gingin 0 00000001
Canberra 0 00000001
Hobart 0 00000001
Estimated Antarctic Regional K Indices 25 May :
Macquarie Island 0 00010000
Casey 2 12100102
Mawson 8 11111115
Observed Regional daily pc3 Indices 25 May :
Darwin 0 (Quiet)
Townsville 0 (Quiet)
Learmonth 13 (Quiet)
Alice Springs 0 (Quiet)
Gingin 0 (Quiet)
Canberra 0 (Quiet)
Melbourne NA
Pc3 pulsations are high frequency (10-45 second period) variations
of the Earths magnetic field. Daily pc3-indices are the daily sum
of 20 minute pc3-indices for that station and have been shown to be
well correlated with rejection of high resolution aeromagnetic
survey flight-line data.
NOTE: Indices may have been generated from data obtained in
cooperation with the following organisations: Geoscience Australia,
University of Newcastle Space Physics Group, Australian Government
Antarctic Division and International Center for Space Weather
Science and Education, Japan.
Estimated AFr/Ap Indices 25 May : A
Fredericksburg 5
Planetary 7
Observed AFr/Ap Indices 24 May : A K
Fredericksburg 2
Planetary 3 2001 0012
2B. MAGNETIC FORECAST
Date Ap Conditions
26 May 40 Quiet to major storm
27 May 30 Mostly active to minor storm declining to unsettled
28 May 15 Mostly unsettled, isolated active periods possible
COMMENT: SWS Geomagnetic Warning 21 was issued on 25 May and
is current for 25-27 May. Geomagnetic conditions in the Australian
and Antarctic region were quiet on UT day 25 May. Quiet to major
storm levels are expected on UT day 26 May and active to minor
storms declining to unsettled level are expected on UT day 27
May, when the 22-23 May CMEs arrive at Earth. The major storms
on 26 May are possible because of the compounding effect of multiple
CMEs. Then unsettled to active conditions are expected on UT
day 28 May.
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3A. GLOBAL HF PROPAGATION SUMMARY
Latitude Band
Date Low Middle High
25 May Normal Normal Normal-fair
PCA Event : No event.
3B. GLOBAL HF PROPAGATION FORECAST
Latitude Band
Date Low Middle High
26 May Normal Normal-fair Normal-fair
27 May Normal-fair Fair Fair-poor
28 May Normal Normal-fair Normal-fair
COMMENT: Mostly normal MUFs are expected on UT day 26 May with
some possible enhancements during the first half of the day followed
by possible minor to moderate depressions. Moderate to significant
MUF depressions could occur on UT day 27 May due to expected
increase in geomagnetic activity with possible slow recovery
in MUFs on 28 May as the geomagnetic activity weakens.
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4A. AUSTRALIAN REGION IONOSPHERIC SUMMARY
Date T index
25 May 8
Observed Australian Regional MUFs
Cocos Island Region:
No data available.
Niue Island Region:
No data available.
Northern Australian Region:
Depressed by 15% during local day.
Near predicted monthly values during local night.
Southern Australian Region:
Near predicted monthly values.
Antarctic Region (Casey/Scott Base/Davis/Mawson):
Enhanced by 30% over the UT day.
Monthly T index:
Month T index
Apr 12
May 21
Jun 24
4B. AUSTRALIAN REGION IONOSPHERIC FORECAST
Date T index MUFs
26 May 5 Near predicted monthly values
27 May 0 Near predicted monthly values/depressed 10 to
30%
28 May 10 Near predicted monthly values/depressed 10 to
20%
COMMENT: SWS HF Communications Warning 17 was issued on 25 May
and is current for 26-27 May. MUFs in the Australian region on
UT day 25 May were mostly near predicted monthly values with
some minor depressions in the Northern Australian region during
the local day. Mostly normal MUFs can be expected on UT day 26
May with some possible enhancements during the first half of
the UT day followed by possible minor to moderate depressions.
Moderate to significant MUF depressions could occur on UT day
27 May due to expected increase in geomagnetic activity with
possible slow recovery in MUFs on 28 May as the geomagnetic activity
weakens.
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5. SPACE ENVIRONMENT SUMMARY
GOES satellite data for 24 May
Daily Proton Fluence >1 MeV: 5.7E+04
Daily Proton Fluence >10 MeV: 4.5E+04
Daily Electron Fluence >2 MeV: 5.50E+07 (normal fluence)
Electron Fluence Daily Deep Dielectric Discharge Probability: 7%
Fluence (flux accumulation over 24hrs)/ cm2-ster-day.
X-ray background: A7.0
DSCOVR Satellite Solar Wind Day Averaged Data for 24 May
Speed: 341 km/sec Density: 2.1 p/cc Temp: 47400 K Bz: 0 nT
(Courtesy Space Weather Prediction Center, Boulder USA)
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Space Weather Services email: asfc at bom.gov.au
Bureau of Meteorology
PO Box 1386 WWW: http://www.sws.bom.gov.au
Haymarket NSW 1240 AUSTRALIA FTP: ftp://ftp-out.sws.bom.gov.au
tel: +61 2 9213 8010 fax: +61 2 9213 8060
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